The invention relates to a method and a device for treatment of the pieced places of a yarn, particularly pieced places in a yarn produced on open end spinning machines, during the drawing off of the yarn from a spinning assembly and before winding on a spool.
There are practically always some pieced places in the yarn on a spool from an open end spinning assembly. These pieced places occur if a yarn break has to be accommodated. It is to be understood that yarn breaks and the projections that result are caused not only by operational disturbances, but also they are many times intentionally produced to maintain a specific yarn quality over a rather long operational time. These pieced places have a strength and appearance that differs from that of the rest of the yarn. To prevent possible flaws in the fabric or the like in material made of the yarn, it used to be customary to clean the spools produced in open end spinning assemblies. Meanwhile however it has been possible to improve the piecing process so that the pieced places have sufficient strength. Cutting out of these pieced places is therefore no longer necessary, especially since the knots produced after the cutting out operation were at least as disturbing in the product made from the yarn as the pieced places were.
The invention is addressed to the problem of treating the pieced places even before winding of the produced yarn on the spools, in such a way that their appearance will be much more closely adapted to the appearance of the rest of the yarn and not show up as thickened places. The problem is solved according to the present invention in that the pieced places are mechanically compacted during the drawing off operation.
By this mechanical compacting, which is limited to the zone of the pieced place, the pieced place which looks more bulky than the rest of the yarn will be equalized with said yarn.
In an advantageous embodiment of the invention it is provided that the pieced places are compressed by pressure elements and rolled about the long axis of the yarn. In this way the yarn in the zone of the pieced places will be rubbed, which will effect a very good equalizing of the pieced places. It is advantageous if at least the beginning of the rolling movement be in the same direction as the spinning part of the yarn. In that way the yarn will not be turned against its twist.
In order to have enough time for the rubbing or the like, it is provided in a further embodiment of the invention that the pressure elements will be capable of being brought up to the running yarn and move during the treatment of the pieced place in the direction of transport of the yarn. For the same purpose, in another embodiment of the invention, it is provided that the pieced places during execution of the treatment will be held by fixedly disposed pressure elements, with production and/or elimination of a yarn reserve.
In a further embodiment of the invention, it is provided that the pieced places will be wetted with a strengthening agent before the mechanical compacting. This strengthening agent, which may comprise a material that can be washed out in a subsequent treatment step, is intended to hold the pieced places in the form given them by the mechanical compacting.
In a further embodiment of the invention, a device for execution of the process is produced, in that pressure elements associated with the yarn are provided, equipped with drive means that can be switched on by controls as a pieced place passes by. More advantageously, the pressure elements have drive and control devices that are components of a travelling piecing device. Of course, it is contemplated to provide pressure elements and the appurtenant drive and control devices on each spinning assembly, but this entails considerably more expense.
These and other objects, features and advantages of the present invention will become more apparent from the following description when taken in connection with the accompanying drawings, which show, for purposes of illustration only, several embodiments in accordance with the present invention.